Long before you were born, the foods your father and grandfather ate, the drugs they took, even the stress they felt—it all started to affect your health, and stranger still, will affect the health of your children.
This idea comes from the field of epigenetics, a fast-growing segment in the world of genetic research. Epigenetics refers to how chemical reactions caused by external or environmental factors, can activate or deactivate genes, almost like a dimmer switch. “Most of us were taught that our traits are hard-coded in the DNA that passes from parent to offspring. Emerging information about epigenetics may lead us to a new understanding of just what inheritance is,” reports the University of Utah Health Sciences. Researchers are finding that epigenetic change can be influenced by things like aging and lifestyle, and are looking at how it can result in diseases such as cancers, coronary heart disease and immune disorders.
A new paper just published in Science sheds more light on how something besides DNA plays a role in our health inheritance. Researchers at McGill University looked at proteins called histones, part of the content of sperm that is used during fertilization, and how these guide embryo development. Using mice as subjects, they slightly tweaked the biochemical information on the histones, and studied the effects on the offspring. This “nick” in the histones had major consequences, with the mice offspring born with birth defects, abnormal skeletons and lower rates of survival. More surprisingly, two generations later, these effects could still be seen.
“When we saw the decreased survivability across generations and the developmental abnormalities, we were really blown away as it was never thought that altering something outside the DNA could be involved in inheritance,” wrote Sarah Kimmins, from McGill’s Dept. of Animal Science, and one of the lead authors on the paper. “These findings are remarkable because they indicate that information other than DNA is involved in heritability. The study highlights the critical role that fathers play in the health of their children and even grandchildren.”
Because changes on the histones are susceptible to environmental exposures, such as stress, diet and chemicals, this discovery will mean new ways of investigating the prevention and treatment of many diseases, across multiple generations.